Surgical instrument including an adapter assembly and an articulating surgical loading unit

ABSTRACT

An adapter assembly includes an articulation nut, an articulation link, and a drive belt operably coupled to a distal portion of the articulation link. The articulation link has a proximal end portion operably coupled to the articulation nut, such that rotation of the articulation nut results in translation of the articulation link. The drive belt has a distal end portion configured to be operably coupled to a proximal end portion of a surgical loading unit, such that movement of the drive belt articulates the surgical loading unit relative to the adapter assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. ProvisionalPatent Application Ser. No. 62/829,801 filed Apr. 5, 2019, the entiredisclosure of which is incorporated by reference herein.

BACKGROUND Technical Field

The present disclosure relates generally to surgical instruments forendoscopic use and, more specifically, to surgical instruments includingadapter assemblies that articulate an attached surgical loading unit.

Background of Related Art

Various types of surgical instruments used to endoscopically treattissue are known in the art, and are commonly used, for example, forclosure of tissue or organs in transection, resection, anastomoses, forocclusion of organs in thoracic and abdominal procedures, and forelectrosurgically fusing or sealing tissue.

One example of such a surgical instrument is a surgical staplinginstrument. Typically, surgical stapling instruments include an endeffector having an anvil assembly and a cartridge assembly forsupporting an array of surgical staples, an approximation mechanism forapproximating the cartridge and anvil assemblies, and a firing mechanismfor ejecting the surgical staples from the cartridge assembly.

During laparoscopic or endoscopic surgical procedures, access to asurgical site is achieved through a small incision or through a narrowcannula inserted through a small entrance wound in a patient. Because oflimited area available to access the surgical site, many endoscopicsurgical instruments include mechanisms for articulating the endeffector of the instrument in relation to a body portion of theinstrument to improve access to tissue to be treated. In addition, someend effectors have a knife shaft that translates therethrough to tissuegrasped by jaws of the end effector. During articulation of the endeffector, the knife shaft experiences a bending moment and/or a shearforce that may degrade the knife shaft over continued articulation ofthe end effector.

Accordingly, it would be beneficial to provide an improved surgicalinstrument, which includes an improved mechanism for articulating theend effector relative to the body portion and without damaging a knifeshaft that moves through the end effector.

SUMMARY

In an aspect of the present disclosure, an adapter assembly is providedand includes an articulation nut, an articulation link, and a drive beltoperably coupled to a distal end portion of the articulation link. Thearticulation link has a proximal end portion operably coupled to thearticulation nut, such that rotation of the articulation nut results intranslation of the articulation link. The drive belt has a distal endportion configured to be operably coupled to a proximal end portion of asurgical loading unit, such that movement of the drive belt articulatesthe surgical loading unit relative to the adapter assembly.

In aspects, the adapter assembly may further include a pulley operablycoupled to a proximal end portion of the drive belt. The drive belt maybe wrapped about the pulley.

In some aspects, the adapter assembly may further include a proximalhousing having the pulley rotationally supported therein, a distalhousing having a distal end portion configured to be pivotably coupledto the proximal end portion of the surgical loading unit, and a tensionscrew disposed between the proximal and distal housings. The tensionscrew may be configured to adjust a distance from which the proximalhousing is spaced from the distal housing and, in turn, adjust a tensionin the belt drive.

In further aspects, the distal end portion of the articulation link maybe operably coupled to a linear section of the drive belt.

In other aspects, the distal end portion of the articulation link mayhave teeth, and the drive belt may have teeth on an inner surfacethereof interfacing with the teeth of the articulation link.

In aspects, the articulation link may include a fin extending from thedistal end portion thereof. The teeth of the articulation link may bedisposed on an outwardly-facing surface of the fin.

In some aspects, the fin of the articulation link may be enclosed by thedrive belt.

In further aspects, the proximal end portion of the articulation linkmay be received in the articulation nut.

In other aspects, the proximal end portion of the articulation link mayhave a threaded outer surface interfacing with a threaded inner surfaceof the articulation nut.

In aspects, the adapter assembly may further include an articulationinput shaft. The articulation nut may have teeth on an outer surfacethereof interfacing with teeth on the articulation input shaft.

In some aspects, the adapter assembly may further include an outerhousing having the articulation nut rotationally supported therein, andan outer tube extending distally from the outer housing. The outer tubemay have the articulation link axially supported therein.

In further aspects, the adapter assembly may further include a rotationgear disposed about the articulation nut and within the outer housing.The rotation gear may be non-rotationally fixed to the outer tube, suchthat the outer tube is configured to rotate about a longitudinal axisthereof in response to a rotation of the rotation gear.

In another aspect of the present disclosure, a surgical instrument isprovided and includes the adapter assembly and a surgical loading unit.The loading unit has a first pulley non-rotationally fixed in a proximalend portion thereof. The drive belt of the adapter assembly has a distalend portion operably coupled to the first pulley, such that movement ofthe drive belt rotates the first pulley to articulate the surgicalloading unit relative to the adapter assembly.

In aspects, the adapter assembly may further include a second pulleyoperably coupled to a proximal end portion of the drive belt. The drivebelt may be wrapped about the first and second pulleys.

In some aspects, the adapter assembly may further include a proximalhousing having the second pulley rotationally supported therein, adistal housing having the first pulley rotationally supported therein,and a tension screw disposed between the proximal and distal housingsand configured to adjust a distance from which the proximal housing isspaced from the distal housing and, in turn, adjust a tension in thebelt drive.

In further aspects, the proximal end portion of the articulation linkmay be received in the articulation nut and may have a threaded outersurface interfacing with a threaded inner surface of the articulationnut.

In other aspects, the surgical loading unit may include an anvil, astaple cartridge assembly pivotably coupled to the anvil, a lead screwdisposed within the staple cartridge assembly, and a knife operablycoupled to the lead screw. The knife may be configured to move throughthe staple cartridge assembly to pivot the staple cartridge assemblytoward the anvil in response to a rotation of the lead screw.

In aspects, the adapter assembly may further include a rotatable driveshaft having a distal end portion coupled to a proximal end portion ofthe lead screw via a universal joint.

BRIEF DESCRIPTION OF THE DRAWINGS

Surgical instruments including embodiments of the presently disclosedadapter assemblies and surgical loading units are disclosed herein withreference to the drawings, wherein:

FIG. 1A is a perspective view of a surgical instrument including anadapter assembly and a surgical loading unit, with a staple cartridgebody of the surgical loading unit shown removed from a chassis of thesurgical loading unit;

FIG. 1B is a perspective view of the surgical instrument of FIG. 1A,with the staple cartridge body of the surgical loading unit showninstalled in the chassis;

FIG. 2 is an exploded view of a proximal end portion of the adapterassembly of FIG. 1A;

FIG. 3 is a side, cross-sectional view of the proximal end portion ofthe adapter assembly;

FIG. 4 is an exploded view of an articulation assembly of the adapterassembly and the surgical loading unit;

FIG. 5 is a side, cross-sectional view of a distal end portion of theadapter assembly and the surgical loading unit;

FIG. 6 is a top view of the distal end portion of the adapter assembly,with an outer tube of the adapter assembly removed, and the surgicalloading unit;

FIG. 7A is a perspective view of an alternate embodiment of a drive beltof the articulation assembly;

FIG. 7B is a perspective view of yet another embodiment of a drive beltof the articulation assembly;

FIG. 8 is a side, perspective view of a surgical loading unit beingarticulated relative to an adapter assembly by another embodiment of anarticulation assembly;

FIG. 9 is an exploded view of the articulation assembly and surgicalloading unit of FIG. 8;

FIG. 10 is a side, perspective view of the adapter assembly of FIG. 8,illustrating a side, cross-section of the surgical loading unit of FIG.8; and

FIG. 11 is a top, cross-sectional view of the articulation assembly ofFIG. 8 shown articulating the surgical loading unit relative to theadapter assembly.

DETAILED DESCRIPTION

Persons skilled in the art will understand that the adapter assembliesand surgical loading units specifically described herein and illustratedin the accompanying drawings are non-limiting exemplary embodiments. Itis envisioned that the elements and features illustrated or described inconnection with one exemplary embodiment may be combined with theelements and features of another without departing from the scope of thepresent disclosure. As well, one skilled in the art will appreciatefurther features and advantages of the disclosure based on the describedembodiments. Accordingly, the disclosure is not to be limited by whathas been particularly shown and described, except as indicated by theappended claims.

As used herein, the term “distal” refers to that portion of the surgicalinstrument which is farthest from a clinician, while the term “proximal”refers to that portion of the surgical instrument which is closest tothe clinician. In addition, as used herein, the term clinician refers tomedical staff including doctors, nurses and support personnel.

The present disclosure is directed to a surgical instrument including anadapter assembly configured to be actuated by a hand-held actuator or asurgical robotic system, and an articulating surgical loading unitcoupled to the adapter assembly. The adapter assembly includes anarticulation mechanism that drives an articulation of the surgicalloading unit relative to the adapter assembly. The articulationmechanism includes an articulation nut, an articulation link thattranslates in response to a rotation of the articulation nut, and abelt-driven pulley system that operably couples the articulation link tothe surgical loading unit. The translation of the articulation linkcauses a belt of the belt-driven pulley system to rotate a pulley fixedto the surgical loading unit, thereby articulating the surgical loadingunit relative to the adapter assembly. The adapter assembly may furtherinclude a rotation gear disposed about the articulation nut andconfigured to rotate the surgical loading unit. The surgical loadingunit may include a lead screw for driving a translation of a knifethrough the surgical loading unit. The lead screw may be operablycoupled to a drive shaft of the adapter assembly via a universal joint.Additional advantages of the presently disclosed surgical instrumentsand components thereof are described below.

FIGS. 1A and 1B illustrate a surgical instrument 10 including a handleassembly 12, an adapter assembly 20 configured to be coupled to thehandle assembly 12, and a surgical loading unit 30 pivotably coupled tothe adapter assembly 20. While the depicted surgical instrument 10 maybe configured to fire staples, it is contemplated that the surgicalinstrument 10 may be adapted to fire any other suitable fastener such asclips and two-part fasteners. Additionally, while the figures depict alinear surgical stapling instrument 10, it is envisioned that certaincomponents described herein may be adapted for use in other types ofendoscopic surgical instruments including non-linear surgical staplerloading units, endoscopic forceps, graspers, dissectors, other types ofsurgical stapling instruments, powered vessel sealing and/or cuttingdevices, etc.

Generally, the adapter assembly 20 of the surgical instrument 10includes an outer housing 21 and an outer tube 24 extending distallyfrom the outer housing 21. The outer housing 21 includes a knob housing22 and a coupling mechanism or proximal housing 25 extending proximallyfrom the knob housing 22 and configured to be operably coupled to thehandle assembly 12 or a surgical robotic system (not shown) responsiblefor actuating the surgical instrument 10. The outer tube 24 has aproximal end portion fixed within the distal end portion of the knobhousing 22. In other embodiments, the outer tube 24 may be rotatablerelative to and within the knob housing 22. The surgical loading unit 30is adapted to be attached to a distal end portion 24 b of the outer tube24 of the adapter assembly 20 and may be configured for a single use, ormay be configured to be used more than once.

The surgical loading unit 30 includes a collar 32 pivotably coupled tothe distal end portion 24 b of the outer tube 24 and an end effector 34supported on the collar 32. The end effector 34 includes an anvil plate36 non-rotationally coupled to the collar 32, and a staple cartridgeassembly 37 disposed in opposed relation with the anvil plate 36. Thestaple cartridge assembly 37 has a chassis 38 pivotably coupled to thecollar 32 and a staple cartridge body 40 configured for removablereceipt in a channel 42 of the chassis 38. As shown in FIG. 4, the anvil26 may have an elongated strain gauge 39 disposed on an undersidethereof and which is electrically connectable to the handle assembly 12to obtain direct and accurate measurement of tissue strain.

For a detailed description of the handle assembly 12, reference may bemade to U.S. Patent Application Publication No. 2015/0157320, filed onNov. 21, 2014, and U.S. Patent Application Publication No. 2016/0310134,filed on Apr. 12, 2016, the entire contents of each of which beingincorporated by reference herein.

With reference to FIGS. 2-6, an articulation mechanism of the adapterassembly 20 will now be described, and is generally designatedarticulation mechanism 81. The adapter assembly 20 includes anarticulation input shaft 50, a firing input shaft 52, and a rotationinput shaft 54 each rotationally supported in the coupling mechanism 25of the outer housing 21 (FIG. 1A). The articulation input shaft 50 has aproximal end portion 50 a configured to be drivingly coupled to acorresponding drive member 13 a of the handle assembly 12 to effect arotation of the articulation input shaft 50. The articulation inputshaft 50 has a distal end portion 50 b having a gear 56 (e.g., a spurgear) fixed thereabout.

The adapter assembly 20 includes an articulation nut 58 operably coupledto the articulation input shaft 50 and operably coupled to anarticulation link 60. The articulation nut 58 may have a ring gear 62 atits proximal end and a tubular shaft 64 extending distally from the ringgear 62. The ring gear 62 of the articulation nut 58 has gear teethinterfacing with the gear 56 of the articulation input shaft 50. Thetubular shaft 64 of the articulation nut 58 has a threaded inner surface66 coupled to a proximal end portion 60 a of the articulation link 60.

The proximal end portion 60 a of the articulation link 60 is received ina channel 68 defined by the tubular shaft 64 of the articulation nut 58.The proximal end portion 60 a of the articulation link 60 has anarcuate, threaded outer surface 70 threadedly engaged with the threadedinner surface 66 of the tubular shaft 64 of the articulation link 60. Assuch, the articulation link 60 translates along a longitudinal axis “X”in response to a rotation of the articulation nut 58. The articulationlink 60 may have a generally elongated, rectangular configuration.However, other shapes of articulation link 60 are contemplated, such astubular. The articulation link 60 defines a longitudinally-extendingpassageway 72 having the firing shaft 52 slidably supported therein.

With reference to FIGS. 4-6, the articulation link 60 has a distal endportion 60 b having a fin 74 extending upwardly therefrom. The fin 74may be a flat, elongated structure. Other shapes of the fin 74 arecontemplated herein. The fin 74 has an outwardly-facing surface 76having teeth 78 (FIG. 6) extending laterally outward therefrom. The fin74 of the articulation link 60 is received in a central cavity 84defined by a drive belt 82 of the articulation mechanism 81, and theteeth 78 of the fin 74 interface with teeth 80 disposed on a linearsection 82 c of the drive belt 82. As such, proximal or distaltranslation of the articulation link 60 drives a movement of the drivebelt 82 along a pathway, such as, for example, an oval-shaped pathway,in either a clockwise or counter-clockwise direction.

The articulation mechanism 81 further includes a proximal pulley 86rotationally supported in the distal end portion 24 b of the outer tube24 of the adapter assembly 20. The proximal pulley 86 has a curved,proximal end portion 82 a of the drive belt 82 wrapped thereabout. Thecollar 32 of the surgical loading unit 30 may act as a distal pulley andis rotationally fixed in the proximal end portion of the surgicalloading unit 30. The collar or distal pulley 32 has a curved, distal endportion 82 b of the drive belt 82 wrapped thereabout. The proximal anddistal pulleys 86, 32 may each have gear teeth interfacing with the gearteeth 80 of the drive belt 82, such that movement of the drive belt 82rotates the pulleys 86, 32. It is contemplated that the proximal pulley86 acts as an idler gear for maintaining tension in the drive belt 82.

The distal pulley 32 may include an upper component 32 a received in theanvil 36 of the surgical loading unit 30 and a lower component 32 breceived in the chassis 38 of the staple cartridge assembly 37 of thesurgical loading unit 30. Each of the upper and lower components 32 a,32 b of the distal pulley 32 has a main body 88 a, 90 a and a gear 88 b,90 b, such as, for example, a pinion gear extending proximally from therespective main body 88 a, 90 a. The main body 88 a of the uppercomponent 32 a is fixed to the anvil 36 of the surgical loading unit 30,and the main body 90 a of the lower component 32 b is fixed to thechassis 38 of the staple cartridge assembly 37 of the surgical loadingunit 30. The gears 88 b, 90 b of the upper and lower components 32 a, 32b are each received in the curved, distal end portion 82 b of the drivebelt 82. The upper and lower components 32 a, 32 b of the distal pulley32 cooperatively define a channel 92 (FIG. 5) through which the curved,distal end portion 82 b of the drive belt 82 extends.

The articulation mechanism 81 further includes a proximal housing 100and a distal housing 102 each disposed in the distal end portion 24 b ofthe outer tube 24 of the adapter assembly 20. The proximal housing 100rotationally supports therein the proximal pulley 86. The proximalhousing 100 is slidable within the outer tube 24, whereas the distalhousing 102 is axially restrained within the outer tube 24. The distalhousing 102 defines an aperture 104 having the gears 88 b, 90 b of thedistal pulley 32 rotationally supported therein. A pivot pin 106 extendsthrough the distal housing 102 and each of the gears 88 b, 90 b of thedistal pulley 32 to pivotably couple the distal pulley 32, and thereforethe surgical loading unit 30 as a whole, to the adapter assembly 20.

The proximal and distal housings 100, 102 are axially spaced from oneanother via a tension screw 108. The tension screw 108 has a proximalend portion 108 a rotationally supported and axially restrained in theproximal housing 100, and a distal end portion 108 b disposed within anelongate channel 110 defined through the distal housing 102. The distalend portion 108 b of the tension screw 108 is threadedly engaged to thedistal housing 102. In this way, a rotation of the tension screw 108adjusts the axial spacing of the proximal housing 100 from the distalhousing 102 by sliding the proximal housing 100 within the outer tube 24and relative to the distal housing 102 in either a proximal or distaldirection. Adjusting the axial spacing between the proximal and distalhousings 100, 102 adjusts the axial spacing between the proximal anddistal pulleys 86, 32, thereby adjusting the tension in the drive belt82.

With reference to FIG. 7A, an alternate embodiment of a drive belt 182is illustrated and which may be used in place of the drive belt 82. Thedrive belt 182 is a band of single or multiple laminations wrapped aboutthe pulleys 86, 32 and instead of having gear teeth, the drive belt 182has a plurality of pins 186 extending radially inward from a distal endportion 182 b of the drive belt 182. The plurality of pins 186 are eachreceived in a corresponding valley defined between adjacent gear teethof the gear 88 b or gears 88 b, 90 b of the distal pulley 32, such thatthe distal pulley 32 rotates in response to movement of the drive belt182. A proximal end portion 182 a of the drive belt 182 may befrictionally engaged to the proximal pulley 86. The drive belt 182 has aplurality of teeth 184 that extend radially inward from an intermediateportion 182 c thereof for fixedly coupling the drive belt 182 to thedistal end portion 60 b (FIG. 4) of the articulation link 60.

With reference to FIG. 7B, another alternate embodiment of a drive belt282 is illustrated and which may be used in place of the drive belt 82.The drive belt 282 is a single or a plurality of cables or wires, whichare wrapped about the proximal and distal pulleys 86, 32. Instead ofhaving gear teeth, an intermediate portion 282 c of the drive belt 282has a first peg 284 a that fixedly couples the drive belt 282 to thedistal end portion 60 b (FIG. 4) of the articulation link 60, and adistal end portion 282 b of the drive belt 282 has a second peg 284 bthat fixedly couples the drive belt 282 to a circumferential edge of thegear 88 b or gears 88 b, 90 b of the distal pulley 32 (FIG. 4). Otherfastening engagements are also contemplated, such as, for example,frictional engagement, adhesives, or the like. A proximal end portion282 a of the drive belt 282 may be frictionally engaged to the proximalpulley 86 (FIG. 4).

In operation, with reference to FIGS. 3-6, to articulate the surgicalloading unit 30 relative to the adapter assembly 20, the articulationinput shaft 50 is rotated via an actuation of the handle assembly 12.The articulation input shaft 50 transfers rotational motion from thegear 56 fixed thereabout to the ring gear 62 of the articulation nut 58.Since the articulation nut 58 is threadedly coupled to the proximal endportion 60 a of the articulation link 60, clockwise rotation of thearticulation nut 58 drives a proximal translation of the articulationlink 60 in the direction indicated by arrow “A” in FIG. 6. The proximaltranslation of the fin 74 of the distal end portion 60 b of thearticulation link 60 b moves the drive belt 82 of the articulationmechanism in a clockwise direction, indicated by arrow “B” in FIG. 6,along the oval pathway defined by the shape of the drive belt 82.

The movement of the drive belt 82 rotates the distal pulley 32 about thepivot pin 106 due to the engagement between the distal end portion 82 bof the drive belt 82 and the gears 88 b, 90 b of the distal pulley 32.Given that the distal pulley 32 is fixed to both the anvil 36 andsurgical cartridge assembly 37 of the surgical loading unit 30, therotation of the distally pulley 32 about the pivot pin 106 causes thesurgical loading unit 30 as a whole to articulate relative to theadapter assembly 20 in the direction indicated by arrow “B” in FIG. 6.Similarly, as can be appreciated, distal movement of the articulationlink 60 in the direction indicated by arrow “C” in FIG. 6 ultimatelyresults in an articulation of the surgical loading unit 30 in thedirection indicated by arrow “D” in FIG. 6.

With reference to FIGS. 2-5, the firing and clamping mechanism of theadapter assembly 20 will now be described. The firing input shaft 52 ofthe adapter assembly 20 is configured to effect a clamping and staplingfunction of the surgical loading unit 30. The firing input shaft 52 hasa proximal end portion 52 a extending through the articulation nut 58and the passageway 72 of the articulation link 60 and is configured tobe drivingly coupled to the drive member 13 b (FIG. 1A) of the handleassembly 12. The firing input shaft 52 has a distal end portion 52 bpivotably and non-rotationally coupled to a proximal end portion 112 aof a lead screw 112 of the surgical loading unit 30.

The lead screw 112 of the surgical loading unit 30 is rotationallysupported in the chassis 38 of the staple cartridge assembly 37. Theproximal end portion 112 a of the lead screw 112 is operably coupled tothe distal end portion 52 b of the firing input shaft 52 via a universaljoint 114. In embodiments, the lead screw 112 and the firing input shaft52 may be coupled via any suitable joint that allows for the transfer ofrotational motion from the firing input shaft 52 to the lead screw 112.

As best shown in FIG. 4, the surgical loading unit 30 further includesan I-beam 116 configured to both sever tissue and pivot the staplecartridge assembly 37 toward the anvil plate 36 during distaladvancement of the I-beam 116. The I-beam 116 has a sharpdistally-oriented surface 118 (forming a knife) configured to severtissue, an upper foot 120 disposed within a ramped channel 121 definedby the anvil plate 36, and a lower foot 122 threadedly engaged with thelead screw 112.

In operation, to fire and clamp the surgical loading unit 30, the firinginput shaft 52 is rotated via an actuation of the handle assembly 12attached to the coupling mechanism 25 of the adapter assembly 20. Thefiring input shaft 52 transfers its rotational motion to the lead screw112 of the surgical loading unit 30 via the universal joint 114.Rotation of the lead screw 112 advances the I-beam 116 distally throughthe anvil plate 36 and the chassis 38, thereby pivoting the chassis 38toward the anvil plate 36 due to the upper foot 120 of the I-beam 116traversing the ramped channel 121 of the anvil 36. As the I-beam 116advances distally through the anvil plate 36 and the chassis 38, anytissue disposed therebetween is severed by the sharp, distally-orientedsurface 118 thereof.

With reference to FIGS. 2 and 3, the rotation mechanism of the adapterassembly 20 will now be described. The rotation input shaft 54 of theadapter assembly 20 has a proximal end portion 54 a configured to bedrivingly coupled to a drive member 13 c (FIG. 1A) of the handleassembly 12 to drive a rotation of the rotation input shaft 54. Therotation input shaft 54 has a gear 126 fixed about a distal end portion54 b thereof. The gear 126 of the rotation input shaft 54 is operablycoupled to teeth 128 of a rotation gear 130 of the rotation mechanism.

The rotation gear 130 is disposed about the tubular shaft 64 of thearticulation nut 58 and within the knob housing 22. A thrust plate 132and a pair of wave springs 134 a, 134 b may be positioned between therotation gear 130 and the articulation nut 58. The rotation gear 130 isfixed to the outer tube 24 via a fastener 136 and keyed to thearticulation link 60, such that the outer tube 24 and the articulationlink 60 are rotatable with the rotation gear 130. In embodiments, anysuitable means for fastening the rotation gear 130 to the outer tube 24may be provided, such as, for example, threaded engagement, frictionalengagement, lock and key engagement, latches, buttons, bayonet-typeconnections, welding, adhesives and/or other mechanisms.

In operation, to rotate the surgical loading unit 30, the rotation inputshaft 54 is rotated via an actuation of the handle assembly 12 attachedto the coupling mechanism 25 of the adapter assembly 20. Rotationalmotion of the rotation input shaft 54 is transferred to the rotationgear 130. Since the rotation gear 130 is locked to the outer tube 24 andthe articulation link 60, rotation of the rotation gear 130 results in arotation of the outer tube 24 relative to the coupling mechanism 25,which, in turn, causes the surgical loading unit 30 to rotate about thelongitudinal axis of the adapter assembly 20.

With reference to FIGS. 8-11, another embodiment of an articulationmechanism for use in the surgical instrument 10 above is illustrated.Due to the similarities between the articulation mechanism of thepresent embodiment and the articulation mechanism described above, onlythose elements of the articulation mechanism of the present embodimentdeemed necessary to elucidate the differences from the articulationmechanism above will be described in detail.

The articulation mechanism includes an articulation rod 140 having aproximal end portion (not explicitly shown) configured to be operablycoupled to a corresponding drive member 13 a (FIG. 1A) of the handleassembly 12. The proximal end portion of the articulation rod 140 isconfigured to translate along a central longitudinal axis “X” of theouter tube 24 of the adapter assembly 20 in response to an activation ofthe drive member 13 a of the handle assembly 12.

The articulation rod 140 has a distal end portion 140 b having a linear,first section 142 a, a linear second section 142 b extending at anobtuse angle from the first section 142 a, and a third section 142 cextending distally from the second section 142 b, whereby the first andthird sections 142 a, 142 c are parallel with one another. Inembodiments, the first, second, and third sections 142 a-c may bedisposed at any suitable angle relative to one another. The firstsection 142 a of the distal end portion 140 b of the articulation rod140 has a collar or E-clip 144 disposed thereabout. A biasing member146, such as, for example, a coil spring, is disposed between the collar144 of the articulation rod 140 and a proximal pivot housing 148 of theadapter assembly 20 for resiliently biasing the articulation rod 140 ina proximal direction to prevent joint backlash.

The proximal pivot housing 148 of the adapter assembly 20 has a proximalend portion 148 a disposed in the distal end portion 24 b of the outertube 24 and a distal end portion 148 b extending distally from thedistal end portion 24 b of the outer tube 24. The third section 142 c ofthe distal end portion 140 b of the articulation rod 140 extends througha longitudinally-extending channel 150 defined through the proximalpivot housing 148 and is laterally offset from the central longitudinalaxis “X” defined by the outer tube 24. The distal end portion 148 b ofthe proximal pivot housing 148 is pivotably coupled to a distal pivothousing 152 fixed to the proximal end portion of the surgical loadingunit 30.

The distal pivot housing 152 of the surgical loading unit 30 has a mainbody 154 fixed within the anvil 36 and chassis 38, and a platform 156extending proximally from the main body 154. The main body 154 and theplatform 156 cooperatively define a slot 158 for receipt of anarticulation link 160. The articulation link 160 has a proximal endportion 160 a pivotably coupled to the third section 142 c of the distalend portion 140 b of the articulation rod 140, and a distal end portion160 b that extends through the slot 158 of the distal pivot housing 152and pivotably couples to the main body 154 of the distal pivot housing152. The articulation link 160 may define a recess 162 in a lateral sidethereof for the passage of a pivot pin 164 that pivotably couples theproximal and distal housings 148, 152 to one another.

In operation, to articulate the surgical loading unit 30 relative to theadapter assembly 20, the articulation rod 140 is translated via anactuation of the handle assembly 12 (FIG. 1A). Since the third section142 c of the distal end portion 140 b of the articulation rod 140 ispivotably coupled to the proximal end portion 160 a of the articulationlink 160, and the distal end portion 160 b of the articulation link 160is pivotably coupled to the distal pivot housing 152 of the surgicalloading unit 30, distal advancement of the articulation rod 140 causesthe articulation link 160 to rotate about the pivot pin 164, whereby thesurgical loading unit 30 articulates about the pivot pin 164 andrelative to the adapter assembly 20. Similarly, as can be appreciated,proximal retraction of the articulation rod 140 drives an articulationof the surgical loading unit 30 in the opposite direction.

It is contemplated that the articulation mechanisms, stapling andclamping mechanisms, and rotation mechanisms described herein may beincorporated into surgical instruments other than surgical instrument10.

Persons skilled in the art will understand that the adapter assembliesand methods specifically described herein and illustrated in theaccompanying drawings are non-limiting exemplary embodiments. It isenvisioned that the elements and features illustrated or described inconnection with one exemplary embodiment may be combined with theelements and features of another without departing from the scope of thepresent disclosure. As well, one skilled in the art will appreciatefurther features and advantages of the disclosure based on theabove-described embodiments. Accordingly, the disclosure is not to belimited by what has been particularly shown and described, except asindicated by the appended claims.

What is claimed is:
 1. An adapter assembly, comprising: an articulationnut; an articulation link having a proximal end portion operably coupledto the articulation nut, such that rotation of the articulation nutresults in translation of the articulation link; a drive belt operablycoupled to a distal end portion of the articulation link, wherein thedrive belt has a distal end portion configured to be operably coupled toa proximal end portion of a surgical loading unit, such that movement ofthe drive belt articulates the surgical loading unit relative to theadapter assembly.
 2. The adapter assembly according to claim 1, furthercomprising a pulley operably coupled to a proximal end portion of thedrive belt, the drive belt being wrapped about the pulley.
 3. Theadapter assembly according to claim 2, further comprising: a proximalhousing having the pulley rotationally supported therein; a distalhousing having a distal end portion configured to be pivotably coupledto the proximal end portion of the surgical loading unit; and a tensionscrew disposed between the proximal and distal housings and configuredto adjust a distance from which the proximal housing is spaced from thedistal housing and, in turn, adjust a tension in the belt drive.
 4. Theadapter assembly according to claim 1, wherein the distal end portion ofthe articulation link is operably coupled to a linear section of thedrive belt.
 5. The adapter assembly according to claim 1, wherein thedistal end portion of the articulation link has teeth, and the drivebelt has teeth on an inner surface thereof interfacing with the teeth ofthe articulation link.
 6. The adapter assembly according to claim 5,wherein the articulation link includes a fin extending from the distalend portion thereof, the teeth of the articulation link being disposedon an outwardly-facing surface of the fin.
 7. The adapter assemblyaccording to claim 6, wherein the fin of the articulation link isenclosed by the drive belt.
 8. The adapter assembly according to claim1, wherein the proximal end portion of the articulation link is receivedin the articulation nut.
 9. The adapter assembly according to claim 8,wherein the proximal end portion of the articulation link has a threadedouter surface interfacing with a threaded inner surface of thearticulation nut.
 10. The adapter assembly according to claim 1, furthercomprising an articulation input shaft, wherein the articulation nut hasteeth on an outer surface thereof interfacing with teeth on thearticulation input shaft.
 11. The adapter assembly according to claim 1,further comprising: an outer housing having the articulation nutrotationally supported therein; and an outer tube extending distallyfrom the outer housing, the outer tube having the articulation linkaxially supported therein.
 12. The adapter assembly according to claim11, further comprising a rotation gear disposed about the articulationnut and within the outer housing, wherein the rotation gear isnon-rotationally fixed to the outer tube, such that the outer tube isconfigured to rotate about a longitudinal axis thereof in response to arotation of the rotation gear.
 13. A surgical instrument, comprising: anadapter assembly including: an articulation nut; an articulation linkhaving a proximal end portion operably coupled to the articulation nut,such that rotation of the articulation nut results in translation of thearticulation link; and a drive belt operably coupled to a distal endportion of the articulation link; and a surgical loading unit having afirst pulley non-rotationally fixed in a proximal end portion thereof,wherein the drive belt has a distal end portion operably coupled to thefirst pulley, such that movement of the drive belt rotates the firstpulley to articulate the surgical loading unit relative to the adapterassembly.
 14. The surgical instrument according to claim 13, wherein theadapter assembly further includes a second pulley operably coupled to aproximal end portion of the drive belt, the drive belt being wrappedabout the first and second pulleys.
 15. The surgical instrumentaccording to claim 14, wherein the adapter assembly further includes: aproximal housing having the second pulley rotationally supportedtherein; a distal housing having the first pulley rotationally supportedtherein; and a tension screw disposed between the proximal and distalhousings and configured to adjust a distance from which the proximalhousing is spaced from the distal housing and, in turn, adjust a tensionin the belt drive.
 16. The surgical instrument according to claim 13,wherein the distal end portion of the articulation link has teeth, andthe drive belt has teeth on an inner surface thereof interfacing withthe teeth of the articulation link.
 17. The surgical instrumentaccording to claim 16, wherein the articulation link includes a finextending from the distal end portion thereof, the teeth of thearticulation link being disposed on an outwardly-facing surface of thefin.
 18. The surgical instrument according to claim 13, wherein theproximal end portion of the articulation link is received in thearticulation nut and has a threaded outer surface interfacing with athreaded inner surface of the articulation nut.
 19. The surgicalinstrument according to claim 13, wherein the surgical loading unitincludes: an anvil; a staple cartridge assembly pivotably coupled to theanvil; a lead screw disposed within the staple cartridge assembly; and aknife operably coupled to the lead screw, the knife being configured tomove through the staple cartridge assembly to pivot the staple cartridgeassembly toward the anvil in response to a rotation of the lead screw.20. The surgical instrument according to claim 19, wherein the adapterassembly further includes a rotatable drive shaft having a distal endportion coupled to a proximal end portion of the lead screw via auniversal joint.